Insert for concrete roads and the like



May 19, 1931. R. ADLER INSERT FOR CONCRETE ROADS AND THE LIKE Filed June 17, 1929 v mm 77056 fZ A 5/67 Patented May 19, 1931 UNITED STATES ROBERT AIJLER, OF ST. PAUL, MINNESOTA INSERT FOR CONCRETE ROADS AND THE LIKE 7 Application filed June 17,

In the construction of hard surfaced roads from concrete and similar plastic compositions it has been found that when the material sets and contracts or settles, or is heaved unequally, cracks are formed. Attempts have been made to control the location of such cracks and at the same time guard against unequal vertical movement of the adjacent parts of the road by embedding metal strips in the formsof the plastic material so as to divide it into rectangular slabs. Adevice of the general type is described in United States Letters Patent Reissue #16,202, granted November 10, 1925, to Bernard Briody. The success of such device is dependent on the weakening effect of the strips, it being assumed that the adhesion of the concrete to the strips is less than the cohesion in the concrete, In practice, it has been found that such devices are frequently ineffectual in controlling the 10- cation of the cracks because of the strong adherence of the plastic material to the strips in the finished structure.

It is the object of this invention to insure the formation of weakened lines in such plastic bodies by providing an insert composed of similar strips mounted face to face one against the other so that the concrete covers and adheres lo the outer surfaces only of the strips. More particularly, it is my object to provide an insert comprising a air of contacting strips adapted to be embe ded in a plastic body along a selected line, the two strips being separable one from the other under contractive stress less than that required to separate the concrete from the faces of the strips. r

The invention will be best understood by reference to the accompanying drawings in which Figure 1 is a diagrammatic cross-section through} a road, showing a suitable location for the insert; Fig. 2 is an enlarged plan view of my insert; Fig. 3 is an enlarged fragmentary section taken on the line 33 of Fig. 1 and showing a suitable clip for excluding plastic composition from between the upper edges of the component members; Fig. 4 is a similar section showing separation of the strips such as that caused by the 1929. Serial No. 371,451.

contracting of the concrete and also showing a suitable filler, such as tar or bituminous material in the crack and Fig. 5 is a vertical section through a slightly modified form of insert imbedded in plastic composition.-

The insert comprises a pair of strips 6 and 7, preferably constructed from non-corroding sheet metal and normally lying one upon the other face to face, with metal to metal contact. Extending longitudinall in the strips 6 and 7 are corrugations 8 which interlock with each other, to form, when imbedded in the concrete or similar plastic body 9, a projecting flange 10 on one of the adjoining portions which engages a groove 5 in the other adjoining portion of the road to retain such portions in proper horizontal alignment. At their lower edges 11 the strips 6 and 7 are preferably joined together or formed integral, as shown in the drawings, so that a hinge-like joint is formed which permits the upper edges of the strips to separate, as shown in Fig. 4, when the road material sets and contracts. To facilitate the operation of securing the inserts in the concrete forms, a series of perforations or openings 17 (Fig. 2) are formed to extend vertically through the projecting corru ations 8. When the inserts are set up sta es 18 may be driven through the openings 17 8 into the sub-soil.

The strips 6 and 7 are placed in the concrete form along the lines where cracks are likely to develop, or where they are desired, and said strips are preferably so located that their upper edges 12 are positioned a short distance beneath the upper surface 13 of the finished body. In some cases, I prefer to'place a channel clip or member 14 over the upper edges 12 to exclude the concrete therefrom, but this is unnecessary in most cases. Where the channel member 14 is used, it extends substantially to the surface 13 so that it can be removed when-it is desired to fill the space formed by the contraction of the material with tar, bitumen, or other filler 15 having the desired melting point.

In Fig. 5 is shown a pair of strips 6 and 7 which are formed wtih corrugations 16 'of slightly modified form, and also showing the strips without the use of the channel member 14. and formed with perforations 19 v and 20 to interlock with the concrete. The

insert and the strips perforations 19 and 20 are staggered so that the plastic composition or concrete cannot extend through both strips 6 and 7 and thereby form a bond tending to prevent separation of said strips. Such perforations insure-the adherence of/the strips to the adjoining bodies of concrete when contraction or other movements creating cracks take place. The perforations 19 and 20 may also be staggered as indicated in Fig. 2.

In use, the plastic composition 9 is poured in the forms so as to completely imbed the strips 6 and 7 leaving an unbroken surface 13. When excessive strain develops either due to the contracting of the material or to unequal settling or heaving, the cracks will develop along the lines weakened by the 6 and 7 will separate from-each other, as indicated in Fig. 4, while adhering to the road material at their outer faces. The crack thus formed in well known manner, after removal of the clip 14, where such clip is used.

Having described my invention what I claim as new and desire to protect by Letters Patent is: I

1. An insert for dividing concrete or similar roads comprising, a pair of stiff, metal strips normally disposed in face to face contact with each other throughout their length and connected together at their lower edges, said strips being adapted to be imbedded in the road body in substantially upright osition and their upper edges being 'separa le upon contraction of said body and registertheir length ing, longitudinal corrugations in said strips perforated to receive means.

2. In aeoncrete or similar road, a pair of stiff, metal strips normally disposed 1n face to face contact with each other throughout and connected together at their said strips being imbedded in the concrete or like body in substantially upright position, their upper edges being separable upon contraction of said body, the lower edges of said strips being substantially in the plane of the lower surface of the concrete and their upper edges spaced beneath the upper surface of the road and registering, longitudinal corrugations in said strips lower edges,

perforated to receive upright supporting means.

In testimony whereof, I have hereunto signed my name to this specification.

' ROBERT ADLER.

aeoaare I filler 15 may be poured into the upright supporting, 

